L-Tyrosine

Also known as: tyrosine, n-acetyl l-tyrosine, NALT

Grade B — Moderate Evidenceamino acidcognitiveperformance
500–2000 mgMorning on empty stomach, or 30 min before demanding task

L-Tyrosine is a non-essential amino acid that serves as the precursor to catecholamine neurotransmitters — dopamine, norepinephrine, and epinephrine. Supplementation is most effective under conditions that deplete catecholamines, such as acute stress, sleep deprivation, cold exposure, and multitasking. Military research shows preserved cognitive performance during demanding scenarios. Under normal, non-stressed conditions, benefits are minimal as tyrosine hydroxylase is already saturated.

TL;DR: Amino acid precursor to dopamine, norepinephrine, and thyroid hormones. Best evidence is for maintaining cognitive performance under stress, sleep deprivation, and multitasking. Take on empty stomach.

🎯Focus🧘Stress & Anxiety🧠Cognitive Performance⚡Energy
Last reviewed: 2026-03-12

Quick Facts

Evidence

Grade B

Studies

2

Interactions

3

Forms

1

Evidence Rating: Grade B — Moderate Evidence

Some RCTs with positive results, or strong observational evidence. More research may refine our understanding.

Interaction Warnings

MAOIsHigh Risk

Tyrosine is a catecholamine precursor — avoid with MAO inhibitors (hypertensive crisis risk).

Thyroid hormones (levothyroxine)Moderate

Tyrosine is a thyroid hormone precursor — may alter thyroid levels.

LevodopaModerate

Competes for same transport system — may reduce levodopa absorption.

Important Notes

  • Most effective under stress, sleep deprivation, or high cognitive demand
  • Less noticeable benefit when already well-rested and unstressed
  • Take on empty stomach for best absorption — competes with other amino acids

Clinical Evidence (2 studies)

Tyrosine promotes cognitive flexibility under stress

Colzato LS et al. (2015) — Psychol Res

Tyrosine supplementation promoted cognitive flexibility (task switching) under demanding conditions

View on PubMed

Tyrosine and working memory in cold stress

Mahoney CR et al. (2007) — Physiol Behav

Tyrosine 150mg/kg eliminated working memory deficits caused by cold exposure

View on PubMed

Alternatives to Consider

These supplements target similar goals and may be worth considering alongside or instead of L-Tyrosine.

L-Theanine

Grade B

Amino acid from green tea. Promotes calm focus (alpha brain waves) without drowsiness. Excellent safety profile.

🎯 Focus🧘 Stress & Anxiety🧠 Cognitive Performance

Creatine Monohydrate

Grade A

One of the most researched supplements in history. Strong evidence for strength, power, and emerging evidence for brain function.

🧠 Cognitive Performance⚡ Energy

Magnesium L-Threonate

Grade B

The only magnesium form shown to cross the blood-brain barrier effectively. Promising for cognitive function and brain aging.

🧠 Cognitive Performance🎯 Focus

Related Supplements

L-Theanine

Grade B — Moderate Evidence

Amino acid from green tea. Promotes calm focus (alpha brain waves) without drowsiness. Excellent safety profile.

Creatine Monohydrate

Grade A — Strong Evidence

One of the most researched supplements in history. Strong evidence for strength, power, and emerging evidence for brain function.

Rhodiola Rosea

Grade B — Moderate Evidence

Adaptogenic herb with strong evidence for reducing stress-related fatigue. Comparable to low-dose antidepressants for mild depression.

Bacopa Monnieri

Grade B — Moderate Evidence

Ayurvedic herb with strong meta-analytic evidence for memory and learning. Requires consistent use for 8-12 weeks.

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⚕️ Important Disclaimer

This information is for educational purposes only. It is not medical advice. Always consult a healthcare provider before starting any supplement regimen, especially if you take medications or have health conditions.

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